Valve construction

ABSTRACT

In a type of combined throttle and trip valve structure, the valve stem has threaded engagement with half nuts; the valve is opened by manual rotation of the stem. Operation of the trip mechanism effects lateral movement of the half nuts out of engagement with the stem and the valve is moved into closed position by spring means. The invention has to do with mechanism to automatically limit the extent of movement of the valve from the valve seat to prevent any jamming of the valve assembly, and to permit the valve to be closed by the spring when the trip mechanism is actuated.

lJnited States [151 Mszmss Schulz et all. 5] Mar. 28, 1972 54] VALVECONSTRUCTION 3,461,893 8/1969 Czuszak ..l37/57X [72] Inventors: Paul W.Scholz, Jeannette; Charles C.

Czuszak, Greensburg, both of Pa.

Assignee:

Filed:

Appl. N0.:

Carrier Corporation, Syracuse, N.Y.

Nov. 24, 1970 References Cited UNITED STATES PATENTS 5/1925 Dunne..251/67 Primary Examiner-Henry T. Klinksiek Att0rney-Harry G. Martin,Jr. and J. Raymond Curtin [5 7] ABSTRACT In a type of combined throttleand trip valve structure, the valve stem has threaded engagement withhalf nuts; the valve is opened by manual rotation of the stem. Operationof the trip mechanism effects lateral movement of the half nuts out ofengagement with the stem and the valve is moved into closed position byspring means. The invention has to do with mechanism to automaticallylimit the extent of movement of the valve from the valve seat to preventany jamming of the valve assembly, and to permit the valve to be closedby the spring when the trip mechanism is actuated.

5 Claims, 5 Drawing Figures PATENTED MR 2 8 I972 FIG! INVENTOR. P W.SCHOLZ BY CH LES ,C. ZZUSZAK ATTORNEY VALVE CONSTRUCTION BACKGROUND OFTHE INVENTION In a conventional combination throttle and trip valve, thevalve is opened by manual rotation of the valve stem which is threadedin a pair of half nuts. These valves are used in conjunction with tripmechanism which in an emergency situation, such as the overspeeding of aturbine, moves the half nuts out of engagement with the stern, whereuponthe valve and the stem are moved rapidly inward by spring means to movethe valve in closed position with the seat. It is possible for theoperator to exert such force on the valve stem when the stem and valveare moved in their outermost position to cause the valve mechanism to bejammed with such tightness that the spring means cannot move the valveto closed position when the trip mechanism is actuated.

SUMMARY OF THE INVENTION This invention has to do with mechanisminvolving a particularly economical structure which may be readilyincorporated with conventional valves of this type, and which functionsautomatically to restrain manual rotation of the valve stem before thevalve mechanism reaches a jamming position and which, however, willreadily permit the valve to be tripped to closed position.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical sectional view ofa conventional throttle and trip valve;

FIG. 2 is an enlarged view of the top portion of the view shown in FIG.1;

FIG. 3 is a view taken on a line corresponding to line 3-3, FIG. 2;

FIG. 4 is a view taken on a line corresponding to line 4-.-4, FIG. 3;and

FIG. 5 is a view taken on a line corresponding to line FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENT The valve structure includes abody having a base portion with inlet and outlet openings 11,12connected by a passage extending through seats 13. The valve 14 is ofthe spool type having axially spaced apart discoidal portions 15 movableinto and out of engagement with the seats 13. The valve 14 is fixed tothe inner end of a valve stem 20, the inner portion of which is slidablymounted in a guide structure 21 formed in the bonnet 22.

A diametrical slot 25 is formed in the upper surface of bonnet 22. Theslot forms a space or track within which half nuts, to be hereinafterdescribed, may slide. Fastened to the top of the bonnet structure 22 asby screws 27 are disc 30 and an annular member 31. A circular member 33having a central bore surrounding the stem in spaced relation thereto ismounted in the bore 34 of the annular member 31, for rotation about theaxis of stem 20. The member 33 is positioned on half nuts 35,37, mountedfor sliding movement in the diametrically extending slot 25. The halfnuts may be considered as threaded restraint means in view of itsselective engagement with stem 20 as will be more fully understood. Apin 40 extends upwardly from each half nut 35,37, into chordallydisposed slots formed in the member 33. The member 33 is retained in thebore 34 of the annular member 31 by a snap ring 41, the peripheralmargin of which extends into a circumferentially extending slot formedin the bore 34.

An actuating rod 48 is fixedly secured to the annular member 33 andextends radially outwardly therefrom through a slot 49 formed in theannular member 31. The actuator 48 is connected to the trip mechanismassociated with the device with which the valve is used, such as a steamturbine. If the speed of the turbine exceeds a predetermined value, thetrip mechanism effects oscillation of the member 33 and through theinstrumentality of the pins 40, the half nut sections 35,37

are moved laterally in the slot 25 out of engagement with the valve stem20, whereupon the stem being free of the threaded restraint provided bythe half nuts is moved downwardly as by spring 50, FIG. 1. Thismechanism, with the exception of the disc 30, is described in detail inU.S. Pat. No. 3,46 l ,893, Aug. 19, 1969, to C. C. Czuszak.

As previously stated, this invention is directed to an arrangement tolimit outward movement of the valve stem 20 and the valve 14 carriedthereby, by manual rotation of the stem in the half nuts 35,37.

As clearly illustrated in the drawings, the valve stem 20 extendsoutwardly through the half nuts 35,37, through the disc 33, and througha cylindrical flange 51 extending upwardly from the disc 30. A handwheel 53 is fixed to the outer end of the stern by being clamped by nut55 against a shoulder formed on the stem and by a key 57.

A detent is mounted on the valve body structure for movement intointerlocking engagement with the valve stem, when the valve is moved bymanual rotation of the hand wheel 53 a predetermined distance from thevalve seats 13.

In the embodiment shown, the cylindrical flange 51 is formed with arecess 60 in which a detent 61 is pivotally mounted by pin 63. The freeend of the detent extends inwardly toward the stem 20. Inasmuch as thehub 65 of hand wheel 53 forms a part of the stem 20 by being fixedlyattached thereto, the hub 65 is formed in proximity to the inner endthereof with a detent engaging portion. The hand wheel hub 65 is formedon its periphery with a recess in the fonn of a notch having a radiallyextending wall 67 merging with a wall 70 extending at right angles tothe wall 67 (see FIG. 5). This notch formation extends outwardly in anaxial direction from the inner end of the hub 65.

When the valve stem has been turned outwardly in the half nuts to movethe valve 14 to open position, the notch formation in the hand wheel hubwill be positioned in registration with the detent 61. The detent 61 isyieldingly urged toward the stem 20 by a spring loaded ball plungerdevice mounted in the flange 51. Accordingly, when the stem has beenthreaded outwardly to position the notch in registration with the detent61, the latter is moved about pivot 63 against the wall 70 of the notch,the end surface of the detent engaging the wall 67 of the notch.Accordingly, the hand wheel cannot be turned further in the directionthreading the stem 20 outwardly. With this engagement by the detent 61,the valve structure 14 is positioned below the guide structure 21,whereby the valve does not become jammed against the guide structure,and there is no tightening action between the stern and the half nuts35,37.

Referring to FIG. 4, the upper end of the notch wall 70 is curvedoutwardly as at 80. Accordingly, if the actuator 48 is operated toeffect disengagement of the half nuts 35,37 from the stem 20, the stemis moved downwardly by spring 50. The curved end surface at the upperend of the notch wall 70 serves as a cam to cam the detent 61 out ofengagement with the notch in the hand wheel hub 65, permitting completeclosing movement of the valve 14 against the seats 13.

It is apparent the wall 67 of the notch serves as a ratchet wheel toothand the detent 61 functions as a pawl which upon engaging the wall 67,as shown in FIG. 3, prevents rotation of the valve stem in the valveopening direction. However, the ratchet and pawl arrangement permits thestem to be rotated in reverse direction or closing the valve. In thelatter case, the detent 61 simply ratchets over the wall 67 of thenotch.

We claim:

1. A combination throttle and trip valve structure including a bodyprovided with a valve seat, selectively operable threaded restraintmeans mounted in the body, a valve stem having threaded engagement withsaid means and extending outwardly from said body, a valve attached tothe inner end of said stem and being movable upon manual rotation ofsaid stern in said means into and out of engagement with said seat,spring means for moving said valve into closed seat engaging positionupon movement of said restraint means out of engagement with said stem;of mechanism for limiting the extent of movement of said valve from saidseat by manual rotation of said stern in one direction, said mechanismcomprising a detent mounted on said body and being movable intoengagement with said stem upon movement of said stem and valve apredetermined distance from said seat, said detent being operable uponsuch engagement with said stem to restrain further rotation thereof insaid one direction, cam means operable upon axial movement of said stemand valve toward said seat by said spring means for moving said detentout of engagement with said stem.

2. A combination throttle and trip valve structure as set forth in claim1 wherein said cam means is formed on said valve stem.

3. A combination throttle and trip valve structure as set forth in claim1 and including means yieldingly urging said detent into engagement withsaid valve stem upon said valve being moved said predetermined distancefrom said seat.

4. A combination throttle and trip valve structure including a bodyprovided with a valve seat, a pair of half nuts mounted in the body, avalve stem having threaded engagement with said half nuts and extendingoutwardly from said body, a valve attached to the inner end of said stemand being movable upon manual rotation of said stem in said nuts intoand out of engagement with said seat, spring means for moving said valveinto closed seat engaging position upon movement of said half nuts outof engagement with said stem; of mechanism for limiting the extent ofmovement of said valve from said seat by manual rotation of said sternin one direction, said mechanism comprising stop means fixed to saidstern, a detent mounted on said body and being movable into engagementwith said stop means upon movement of said stem and valve apredetermined distance from said seat, said detent being operable uponsuch engagement with said stop means to restrain further rotation ofsaid stem in said one direction, said stem being provided with a camsurface, cam means operable, upon movement of said stem and valve towardsaid seat by said spring means, for moving said detent out of engagementwith said stop means.

5. A combination throttle and trip valve structure as set forth in claim4 wherein said stop means consists of a ratchet tooth and said detent isyieldingly urged into engagement with said ratchet to the upon saidvalve being moved a predetermined distance from said seat.

1. A combination throttle and trip valve structure including a bodyprovided with a valve seat, selectively operable threaded restraintmeans mounted in the body, a valve stem having threaded engagement withsaid means and extending outwardly from said body, a valve attached tothe inner end of said stem and being movable upon manual rotation ofsaid stem in said means into and out of engagement with said seat,spring means for moving said valve into closed seat engaging positionupon movement of said restraint means out of engagement with said stem;of mechanism for limiting the extent of movement of said valve from saidseat by manual rotation of said stem in one direction, said mechanismcomprising a detent mounted on said body and being movable intoengagement with said stem upon movement of said stem and valve apredetermined distance from said seat, said detent being operable uponsuch engagement with said stem to restrain further rotation thereof insaid one direction, cam means operable upon axial movement of said stemand valve toward said seat by said spring means for moving said detentout of engagement with said stem.
 2. A combination throttle and tripvalve structure as set forth in claim 1 wherein said cam means is formedon said valve stem.
 3. A combination throttle and trip valve structureas set forth in claim 1 and including means yieldingly urging saiddetent into engagement with said valve stem upon said valve being movedsaid predetermined distance from said seat.
 4. A combination throttleand trip valve structure including a body provided with a valve seat, apair of half nuts mounted in the body, a valve stem having threadedengagement with said half nuts and extending outwardly from said body, avalve attached to the inner end of said stem and being movable uponmanual rotation of said stem in said nuts into and out of engagementwith said seat, spring means for moving said valve into closed seatengaging position upon movement of said half nuts out of engagement withsaid stem; of mechanism for limiting the extent of movement of saidvalve from said seat by manual rotation of said stem in one direction,said mechanism comprising stop means fixed to said stem, a detentmounted on said body and being movable into engagement with said stopmeans upon movement of said stem and valve a predetermined distance fromsaid seat, said detent being operable upon such engagement with saidstop means to restrain further rotation of said stem in said onedirection, said stem being provided with a cam surface, cam meansoperable, upon movement of said stem and valve toward said seat by saidspring means, for moving said detent out of engagement with said stopmeans.
 5. A combination throttle and trip valve structure as set forthin claim 4 wherein said stop means consists of a ratchet tooth and saiddetent is yieldingly urged into engagement with said ratchet to the uponsaid valve being moved a predetermined distance from said seat.